It is known that pickup trucks have a cargo box mounted on the vehicle rearward of the cab. This box consists of a floor, sidewalls, a front wall, and a pivoting tailgate. The typical truck bed's width spans more than four feet but each of the sidewalls has a wheel housing that projects inward from the sidewalls, thereby reducing the width of the useful floor space. Sport-utility vehicles are similarly constructed, including a floor, sidewalls, and wheel housings that project inward from the sidewalls.
Vehicles such as pickup trucks and sport utility vehicles are often used to carry construction materials such as sheets of drywall or plywood. In some cases these sheet materials cannot be laid flat on the vehicle floor because the size of the sheet material exceeds the dimension between the wheel housings. Thus sheet materials must be tilted at an angle, and then the edge of the sheet material is susceptible to damage as it rides against the wheel housing.
It would be desirable to provide a convenient mechanism by which large size sheet materials could be carried in a horizontal position rather than a tilted position engaging against the wheel housing. It would also be desirable to provide a convenient mechanism by which a two-tier storage system could be created for carrying a cargo of tools and construction materials.